RE: [PATCH 2/2 v5] Fix reverse stepping multiple contiguous PC ranges over the line table.

Carl Love via Gdb-patches
2023-06-22T20:38:45Z

Simon:

On Mon, 2023-06-19 at 13:58 -0400, Simon Marchi wrote:
<snip>

>
100644
> > --- a/gdb/infrun.c
> > +++ b/gdb/infrun.c
> > @@ -114,6 +114,9 @@ static struct async_event_handler
> > *infrun_async_inferior_event_token;
> > Starts off as -1, indicating "never enabled/disabled". */
> > static int infrun_is_async = -1;
> >
> > +static CORE_ADDR update_line_range_start (CORE_ADDR pc,
> > + struct
> > execution_control_state *ecs);
> > +
>
> This forward-declaration is not needed.

I tried removing the forward-declaration and the compile fails with the
message:

../../binutils-gdb-reverse-multiple-contiguous/gdb/infrun.c:6773:1:
error: no previous declaration for ‘CORE_ADDR
update_line_range_start(CORE_ADDR, execution_control_state*)’ [-
Werror=missing-declarations]
6773 | update_line_range_start (CORE_ADDR pc, struct
execution_control_state *ecs)
| ^~~~~~~~~~~~~~~~~~~~~~~
cc1plus: all warnings being treated as errors
make[2]: *** [Makefile:1922: infrun.o] Error 1
make[2]: Leaving directory '/home/carll/GDB/build-reverse-multiple-
contiguous/gdb'
make[1]: *** [Makefile:13569: all-gdb] Error 2
make[1]: Leaving directory '/home/carll/GDB/build-reverse-multiple-
contiguous'
make: *** [Makefile:1005: all] Error 2

Leaving the forward declaration in the code.

>
> > /* See infrun.h. */
> >
> > void
> > @@ -6769,6 +6772,25 @@ handle_signal_stop (struct
> > execution_control_state *ecs)
> > process_event_stop_test (ecs);
> > }
> >
> > +CORE_ADDR
> > +update_line_range_start (CORE_ADDR pc, struct
> > execution_control_state *ecs)
>
> Please add a comment for the function.

Done.

>
> > +{
> > + /* The line table may have multiple entries for the same source
> > code line.
> > + Given the PC, check the line table and return the PC that
> > corresponds
> > + to the line table entry for the source line that PC is
> > in. */
> > + CORE_ADDR start_line_pc = ecs->event_thread-
> > >control.step_range_start;
> > + gdb::optional<CORE_ADDR> real_range_start;
> > +
> > + /* Call find_line_range_start to get the smallest address in the
> > + linetable for multiple Line X entries in the line table. */
> > + real_range_start = find_line_range_start (pc);
> > +
> > + if (real_range_start.has_value ())
> > + start_line_pc = *real_range_start;
> > +
> > + return start_line_pc;
>
> When I read this, I wonder: why was control.step_range_start not set
> to
> the "real" range start in the first place (not only in the context of
> reverse execution, every time it is set)? It would seem more robust
> than patching it afterwards in some very specific spots.
>
> I could see some benefits for range-stepping uses cases too (relevant
> when debugging remotely). Using your example here:
>
> Line X - [0x0 - 0x8]
> Line X - [0x8 - 0x10]
> Line X - [0x10 - 0x18]
>
> Imagine we are stopped at 0x14, and we type "next", and 0x14 is a
> conditional jump to 0x5. It seems like current GDB would send a
> "range
> step" request to GDBserver, to step in the [0x10, 0x18[ range. When
> reaching 0x5, execution would stop, and GDB would resume it again
> with
> the [0x0,0x8[ range. When reaching 0x8, it would stop again, GDB
> would
> resume it with [0x8,0x10[, and so on. If GDB could send a "range
> step"
> request with the [0x0,0x18[ range, it would avoid those unnecessary
> intermediary stop.
>
> > +}
> > +
> > /* Come here when we've got some debug event / signal we can
> > explain
> > (IOW, not a random signal), and test whether it should cause a
> > stop, or whether we should resume the inferior (transparently).
> > @@ -7570,6 +7592,28 @@ process_event_stop_test (struct
> > execution_control_state *ecs)
> >
> > if (stop_pc_sal.is_stmt)
> > {
> > + if (execution_direction == EXEC_REVERSE)
> > + {
> > + /* We are stepping backwards make sure we have reached
> > the
> > + beginning of the line. */
> > + CORE_ADDR stop_pc = ecs->event_thread->stop_pc ();
> > + CORE_ADDR start_line_pc
> > + = update_line_range_start (stop_pc, ecs);
> > +
> > + if (stop_pc != start_line_pc)
> > + {
> > + /* Have not reached the beginning of the source code
> > line.
> > + Set a step range. Execution should stop in any
> > function
> > + calls we execute back into before reaching the
> > beginning
> > + of the line. */
> > + ecs->event_thread->control.step_range_start =
> > start_line_pc;
> > + ecs->event_thread->control.step_range_end = stop_pc;
> > + set_step_info (ecs->event_thread, frame,
> > stop_pc_sal);
> > + keep_going (ecs);
> > + return;
> > + }
> > + }
> > +
> > /* We are at the start of a statement.
> >
> > So stop. Note that we don't stop if we step into the
> > middle of a
> > @@ -7632,6 +7676,19 @@ process_event_stop_test (struct
> > execution_control_state *ecs)
> > set_step_info (ecs->event_thread, frame, stop_pc_sal);
> >
> > infrun_debug_printf ("keep going");
> > +
> > + if (execution_direction == EXEC_REVERSE)
> > + {
> > + CORE_ADDR stop_pc = ecs->event_thread->stop_pc ();
> > +
> > + /* Make sure the stop_pc is set to the beginning of the
> > line. */
> > + if (stop_pc != ecs->event_thread->control.step_range_start)
> > + {
> > + stop_pc = update_line_range_start (stop_pc, ecs);
> > + ecs->event_thread->control.step_range_start = stop_pc;
> > + }
> > + }
> > +
> > keep_going (ecs);
> > }
> >
> > diff --git a/gdb/symtab.c b/gdb/symtab.c
> > index 27611a34ec4..91d35616eb9 100644
> > --- a/gdb/symtab.c
> > +++ b/gdb/symtab.c
> > @@ -3282,6 +3282,55 @@ find_pc_line (CORE_ADDR pc, int notcurrent)
> > return sal;
> > }
> >
> > +/* Compare two symtab_and_line entries. Return true if both have
> > + the same line number and the same symtab pointer. That means
> > we
> > + are dealing with two entries from the same line and from the
> > same
> > + source file.
> > +
> > + Return false otherwise. */
> > +
> > +static bool
> > +sal_line_symtab_matches_p (const symtab_and_line &sal1,
> > + const symtab_and_line &sal2)
> > +{
> > + return (sal1.line == sal2.line && sal1.symtab == sal2.symtab);
>
> Unnecessary parenthesis.

Removed unnecessary parenthesis.

>
> > +}
> > +
> > +/* See symtah.h. */
> > +
> > +gdb::optional<CORE_ADDR>
> > +find_line_range_start (CORE_ADDR pc)
> > +{
> > + struct symtab_and_line current_sal = find_pc_line (pc, 0);
> > +
> > + if (current_sal.line == 0)
> > + return {};
> > +
> > + struct symtab_and_line prev_sal = find_pc_line (current_sal.pc -
> > 1, 0);
> > +
> > + /* If the previous entry is for a different line, that means we
> > are already
> > + at the entry with the start PC for this line. */
> > + if (!sal_line_symtab_matches_p (prev_sal, current_sal))
> > + return current_sal.pc;
> > +
> > + /* Otherwise, keep looking for entries for the same line but
> > with
> > + smaller PC's. */
> > + bool done = false;
> > + CORE_ADDR prev_pc;
> > + while (!done)
> > + {
> > + prev_pc = prev_sal.pc;
> > +
> > + prev_sal = find_pc_line (prev_pc - 1, 0);
> > +
> > + /* Did we notice a line change? If so, we are done with the
> > search. */
> > + if (!sal_line_symtab_matches_p (prev_sal, current_sal))
> > + done = true;
> > + }
> > +
> > + return prev_pc;
>
> Algorithmic complexity question: given that line tables are sorted by
> address, would it work to start at the current line table item, and
> go
> look at the previous ones until we find one that is no longer
> contiguous and same line? find_pc_line is somewhat heavy, so if we
> don't need to do it repeatedly...
>
> > +}
> > +
> > /* See symtab.h. */
> >
> > struct symtab *
> > diff --git a/gdb/symtab.h b/gdb/symtab.h
> > index 404d0ab30a8..f54305636da 100644
> > --- a/gdb/symtab.h
> > +++ b/gdb/symtab.h
> > @@ -2346,6 +2346,22 @@ extern struct symtab_and_line find_pc_line
> > (CORE_ADDR, int);
> > extern struct symtab_and_line find_pc_sect_line (CORE_ADDR,
> > struct obj_section *,
> > int);
> >
> > +/* Given PC, and assuming it is part of a range of addresses that
> > is part of a
> > + line, go back through the linetable and find the starting PC of
> > that
> > + line.
> > +
> > + For example, suppose we have 3 PC ranges for line X:
> > +
> > + Line X - [0x0 - 0x8]
> > + Line X - [0x8 - 0x10]
> > + Line X - [0x10 - 0x18]
> > +
> > + If we call the function with PC == 0x14, we want to return 0x0,
> > as that is
> > + the starting PC of line X, and the ranges are contiguous.
>
> I think that putting this example in the comment is great. It makes
> it
> much more obvious what the function specifically does.
>
> > +*/
> > +
> > +extern gdb::optional<CORE_ADDR> find_line_range_start (CORE_ADDR
> > pc);
> > +
> > /* Wrapper around find_pc_line to just return the symtab. */
> >
> > extern struct symtab *find_pc_line_symtab (CORE_ADDR);
> > diff --git a/gdb/testsuite/gdb.reverse/func-map-to-same-line.c
> > b/gdb/testsuite/gdb.reverse/func-map-to-same-line.c
> > new file mode 100644
> > index 00000000000..da944874e86
> > --- /dev/null
> > +++ b/gdb/testsuite/gdb.reverse/func-map-to-same-line.c
> > @@ -0,0 +1,36 @@
> > +/* Copyright 2008-2023 Free Software Foundation, Inc.
> > +
> > + This program is free software; you can redistribute it and/or
> > modify
> > + it under the terms of the GNU General Public License as
> > published by
> > + the Free Software Foundation; either version 3 of the License,
> > or
> > + (at your option) any later version.
> > +
> > + This program is distributed in the hope that it will be useful,
> > + but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> > + GNU General Public License for more details.
> > +
> > + You should have received a copy of the GNU General Public
> > License
> > + along with this program. If not, see <
> > http://www.gnu.org/licenses/
> > >.
> > +
> > + This test is used to test the reverse-step and reverse-next
> > instruction
> > + execution for a source line that contains multiple function
> > calls. */
> > +
> > +void
> > +func1 ()
> > +{
> > +} /* END FUNC1 */
> > +
> > +void
> > +func2 ()
> > +{
> > +} /* END FUNC2 */
> > +
> > +int main ()
>
> int
> main (void)
>

Fixed.

> > +{
> > + int a, b;
> > + a = 1;
> > + b = 2;
> > + func1 (); func2 ();
> > + a = a + b; /* START REVERSE TEST */
> > +}
> > diff --git a/gdb/testsuite/gdb.reverse/func-map-to-same-line.exp
> > b/gdb/testsuite/gdb.reverse/func-map-to-same-line.exp
> > new file mode 100644
> > index 00000000000..89e226b0f84
> > --- /dev/null
> > +++ b/gdb/testsuite/gdb.reverse/func-map-to-same-line.exp
> > @@ -0,0 +1,140 @@
> > +# Copyright 2008-2023 Free Software Foundation, Inc.
> > +
> > +# This program is free software; you can redistribute it and/or
> > modify
> > +# it under the terms of the GNU General Public License as
> > published by
> > +# the Free Software Foundation; either version 3 of the License,
> > or
> > +# (at your option) any later version.
> > +#
> > +# This program is distributed in the hope that it will be useful,
> > +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> > +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> > +# GNU General Public License for more details.
> > +#
> > +# You should have received a copy of the GNU General Public
> > License
> > +# along with this program. If not, see <
> > http://www.gnu.org/licenses/
> > >. */
> > +
> > +# This file is part of the GDB testsuite. It tests reverse
> > stepping.
> > +# Lots of code borrowed from "step-test.exp".
> > +
> > +# This test checks to make sure there is no regression failures
> > for
> > +# the reverse-next command when stepping back over two functions
> > in
> > +# the same line.
> > +
> > +require supports_reverse
> > +
> > +# This test uses the gcc no-column-info command which was added in
> > gcc 7.1.
> > +
> > +proc run_tests {} {
> > + global srcfile
> > + global executable
> > +
> > + runto_main
>
> We typically check for runto_main's success:

Fixed two instances of runto_main in this test case and two in the
other test case.

>
> if { ![runto_main] } {
> return
> }
>
> runto_main logs a FAIL on failure. There are a few runto_mains in
> the
> patch.
>
> > + set target_remote [gdb_is_target_remote]
>
> target_remote seems unused

Removed.

>
> > +
> > + with_test_prefix "test1" {
> > + gdb_test_no_output "record" "turn on process record"
> > + }
>
> with_test_prefix with a single test in it is really just the same as:
>
> gdb_test_no_output "record" "test1: turn on process record"
>
> In fact, you have some other tests with the "test1:" or "test2:"
> prefix,
> I think they should be moved to the with_test_prefix. And maybe use
> "next" and "step" instead of "test1" and "test2".

Yup, cleaner to have the with_test_prefix cover the whole test.
Changed test1 to next-test and test2 to step-next.

>
> > +
> > + # This regression test verifies the reverse-step and reverse-
> > next commands
> > + # work properly when executing backwards thru a source line
> > containing
> > + # two function calls on the same source line, i.e. func1 ();
> > func2 ();
> > + # This test is compiled so the dwarf info not contain the line
> > table
> > + # information.
> > +
> > + # Test 1, reverse-next command
> > + # Set breakpoint at the line after the function calls.
> > + set bp_start_reverse_test [gdb_get_line_number "START REVERSE
> > TEST" \
> > + $srcfile]
> > + gdb_breakpoint $srcfile:$bp_start_reverse_test temporary
> > +
> > + # Continue to break point for reverse-next test.
> > + # Command definition: reverse-next [count]
> > + # Run backward to the beginning of the previous line
> > executed in the
> > + # current (innermost) stack frame. If the line contains
> > function calls,
> > + # they will be “un-executed” without stopping. Starting from
> > the first
> > + # line of a function, reverse-next will take you back to the
> > caller of
> > + # that function, before the function was called, just as the
> > normal next
> > + # command would take you from the last line of a function
> > back to its
> > + # return to its caller 2 .
> > + gdb_continue_to_breakpoint \
> > + "test1: stopped at command reverse-next test start location" \
> > + ".*$srcfile:$bp_start_reverse_test\r\n.*"
> > +
> > + # The reverse-next should step all the way back to the
> > beginning of the
> > + # line, i.e. at the beginning of the func1 call.
> > + gdb_test "reverse-next" ".*func1 \\(\\); func2 \\(\\);.*" \
> > + "test1: reverse-next to line with two functions"
> > +
> > + # We should be stopped at the first instruction of the line. A
> > reverse-step
> > + # should step back and stop at the beginning of the previous
> > line b = 2,
> > + # i.e. not in func1 ().
> > + gdb_test "reverse-stepi" ".*b = 2;.*" \
> > + "test1: reverse-stepi to previous line b = 2"
> > +
> > +
> > + # Setup for test 2
> > + clean_restart $executable
> > + runto_main
> > +
> > + with_test_prefix "test2" {
> > + gdb_test_no_output "record" "turn on process record"
> > + }
> > +
> > + # Test 2, reverse-step command
> > + # Set breakpoint at the line after the function calls.
> > + gdb_breakpoint $srcfile:$bp_start_reverse_test temporary
> > +
> > + # Continue to the start of the reverse-step test.
> > + # Command definition: reverse-step [count]
> > + # Run the program backward until control reaches the start
> > of a
> > + # different source line; then stop it, and return control
> > to gdb.
> > + # Like the step command, reverse-step will only stop at the
> > beginning
> > + # of a source line. It “un-executes” the previously
> > executed source
> > + # line. If the previous source line included calls to
> > debuggable
> > + # functions, reverse-step will step (backward) into the
> > called function,
> > + # stopping at the beginning of the last statement in the
> > called
> > + # function (typically a return statement). Also, as with
> > the step
> > + # command, if non-debuggable functions are called, reverse-
> > step will
> > + # run thru them backward without stopping.
> > +
> > + gdb_continue_to_breakpoint \
> > + "test2: stopped at command reverse-step test start location" \
> > + ".*$srcfile:$bp_start_reverse_test\r\n.*"
> > +
> > + # The first reverse step should take us call of func2 ().
> > + gdb_test "reverse-step" ".*END FUNC2.*" \
> > + "test2: reverse-step into func2 "
> > +
> > + # The second reverse step should take us into func1 ().
> > + gdb_test "reverse-step" ".*END FUNC1.*" \
> > + "test2: reverse-step into func1 "
> > +
> > + # The third reverse step should take us call of func1 ().
> > + gdb_test "reverse-step" ".*func1 \\(\\); func2 \\(\\);.*" \
> > + "test2: reverse-step to line func1(); func2(), at call for
> > func1 "
> > +
> > + # We should be stopped at the first instruction of the line. A
> > reverse
> > + # stepi should take us to b = 2 ().
> > + gdb_test "reverse-stepi" ".*b = 2;.*" \
> > + "test2: reverse-stepi to line b = 2 "
> > +}
> > +
> > +set srcfile func-map-to-same-line.c
> > +set executable func-map-to-same-line
>
> Wondering if this test should use standard_testfile (like almost
> every
> other tests) to set these.

OK, changed to use the standard_testfile.

>
> > +
> > +# test with and without gcc column info enabled
> > +foreach_with_prefix with_column_info {yes no} {
> > + if {$with_column_info == "yes"} {
> > + set options [list debug column-info]
> > + } else {
> > + set options [list debug no-column-info]
> > + }
>
> I didn't think of this when proposing the foreach_with_prefix, but
> you
> could perhaps use:
>
> foreach_with_prefix column_info_flag {column-info no-column-info}
>
> ... to avoid this boilerplate. You can then use $column_info_flag
> directly when setting options.
>
OK, that cleans things up a bit. Changed.
+
+ if {[build_executable "failed to prepare" $executable $srcfile
\
+ $options] == -1} {
+ return -1
+ }
+
+ clean_restart $executable

clean_restart can go in run_tests.

+ run_tests
+}
diff --git a/gdb/testsuite/gdb.reverse/map-to-same-line.c
b/gdb/testsuite/gdb.reverse/map-to-same-line.c
new file mode 100644
index 00000000000..f20d778f40e
--- /dev/null
+++ b/gdb/testsuite/gdb.reverse/map-to-same-line.c
@@ -0,0 +1,58 @@
+/* Copyright 2008-2023 Free Software Foundation, Inc.

Just wondering if the copyright years are right.

New files so yea, should just start with 2023.
>
+
+ This program is free software; you can redistribute it and/or
modify
+ it under the terms of the GNU General Public License as
published by
+ the Free Software Foundation; either version 3 of the License,
or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public
License
+ along with this program. If not, see <
http://www.gnu.org/licenses/
>. */
+
+/* The purpose of this test is to create a DWARF line table that
contains two
+ or more entries for the same line. When stepping (forwards or
backwards),
+ GDB should step over the entire line and not just a particular
entry in the
+ line table. */
+
+int
+main ()

void in the parenthesis

Fixed in both test files.

>
+{ /* TAG: main prologue */
+ asm ("main_label: .globl main_label");
+ int i = 1, j = 2, k;
+ float f1 = 2.0, f2 = 4.1, f3;
+ const char *str_1 = "foo", *str_2 = "bar", *str_3;
+
+ asm ("line1: .globl line1");
+ k = i; f3 = f1; str_3 = str_1; /* TAG: line 1 */
+
+ asm ("line2: .globl line2");
+ k = j; f3 = f2; str_3 = str_2; /* TAG: line 2 */
+
+ asm ("line3: .globl line3");
+ k = i; f3 = f1; str_3 = str_1; /* TAG: line 3 */
+
+ asm ("line4: .globl line4");
+ k = j; f3 = f2; str_3 = str_2; /* TAG: line 4 */
+
+ asm ("line5: .globl line5");
+ k = i; f3 = f1; str_3 = str_1; /* TAG: line 5 */
+
+ asm ("line6: .globl line6");
+ k = j; f3 = f2; str_3 = str_2; /* TAG: line 6 */
+
+ asm ("line7: .globl line7");
+ k = i; f3 = f1; str_3 = str_1; /* TAG: line 7 */
+
+ asm ("line8: .globl line8");
+ k = j; f3 = f2; str_3 = str_2; /* TAG: line 8 */
+
+ asm ("main_return: .globl main_return");
+ k = j; f3 = f2; str_3 = str_2; /* TAG: main return */
+
+ asm ("end_of_sequence: .globl end_of_sequence");
+ return 0; /* TAG: main return */
+}
diff --git a/gdb/testsuite/gdb.reverse/map-to-same-line.exp
b/gdb/testsuite/gdb.reverse/map-to-same-line.exp
new file mode 100644
index 00000000000..16a359d90ec
--- /dev/null
+++ b/gdb/testsuite/gdb.reverse/map-to-same-line.exp
@@ -0,0 +1,156 @@
+# Copyright 2008-2023 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or
modify
+# it under the terms of the GNU General Public License as
published by
+# the Free Software Foundation; either version 3 of the License,
or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public
License
+# along with this program. If not, see <
http://www.gnu.org/licenses/
= >.
+
+# When stepping (forwards or backwards), GDB should step over the
entire line
+# and not just a particular entry in the line table. This test was
added to
+# verify the find_line_range_start function properly sets the step
range for a
+# line that consists of multiple statements, i.e. multiple entries
in the line
+# table. This test creates a DWARF line table that contains two
entries for
+# the same line to do the needed testing.
+
+# This test can only be run on targets which support DWARF-2 and
use gas.
+load_lib dwarf.exp
+require dwarf2_support
+
+# The DWARF assembler requires the gcc compiler.
+require is_c_compiler_gcc
+
+# This test suitable only for process that can do reverse
execution
+require supports_reverse
+
+standard_testfile .c .S
+
+if { [prepare_for_testing "failed to prepare" ${testfile}
${srcfile}] } {
+ return -1
+}
+
+set asm_file [standard_output_file $srcfile2]
+Dwarf::assemble $asm_file {
+ global srcdir subdir srcfile
+ declare_labels integer_label L
+
+ # Find start address and length of program
+ lassign [function_range main [list
${srcdir}/${subdir}/$srcfile]] \
+ main_start main_len
+ set main_end "$main_start + $main_len"
+
+ cu {} {
+ compile_unit {
+ {language @DW_LANG_C}
+ {name map-to-same-line.c}
+ {stmt_list $L DW_FORM_sec_offset}
+ {low_pc 0 addr}
+ } {
+ subprogram {
+ {external 1 flag}
+ {name main}
+ {low_pc $main_start addr}
+ {high_pc $main_len DW_FORM_data4}
+ }
+ }
+ }
+
+ lines {version 2 default_is_stmt 1} L {
+ include_dir "${srcdir}/${subdir}"
+ file_name "$srcfile" 1
+
+ # Generate the line table program with distinct source lines
being
+ # mapped to the same line entry. Line 1, 5 and 8 contain 1
statement
+ # each. Line 2 contains 2 statements. Line 3 contains 3
statements.
+ program {
+ DW_LNE_set_address $main_start
+ line [gdb_get_line_number "TAG: main prologue"]
+ DW_LNS_copy
+ DW_LNE_set_address line1
+ line [gdb_get_line_number "TAG: line 1" ]
+ DW_LNS_copy
+ DW_LNE_set_address line2
+ line [gdb_get_line_number "TAG: line 2" ]
+ DW_LNS_copy
+ DW_LNE_set_address line3
+ line [gdb_get_line_number "TAG: line 2" ]
+ DW_LNS_copy
+ DW_LNE_set_address line4
+ line [gdb_get_line_number "TAG: line 3" ]
+ DW_LNS_copy
+ DW_LNE_set_address line5
+ line [gdb_get_line_number "TAG: line 3" ]
+ DW_LNS_copy
+ DW_LNE_set_address line6
+ line [gdb_get_line_number "TAG: line 3" ]
+ DW_LNS_copy
+ DW_LNE_set_address line7
+ line [gdb_get_line_number "TAG: line 5" ]
+ DW_LNS_copy
+ DW_LNE_set_address line8
+ line [gdb_get_line_number "TAG: line 8" ]
+ DW_LNS_copy
+ DW_LNE_set_address main_return
+ line [gdb_get_line_number "TAG: main return"]
+ DW_LNS_copy
+ DW_LNE_set_address end_of_sequence
+ DW_LNE_end_sequence
+ }
+ }
+}
+
+if { [prepare_for_testing "failed to prepare" ${testfile} \
+ [list $srcfile $asm_file] {nodebug} ] } {
+ return -1
+}
+
+runto_main
+
+# Print the line table
+gdb_test_multiple "maint info line-table ${testfile}" "" {
+ -re "\r\n$decimal\[ \t\]+$decimal\[ \t\]+($hex)\[
\t\]+Y\[^\r\n\]*" {
+ lappend is_stmt $expect_out(1,string)
+ exp_continue
+ }
+ -re -wrap "" {
+ }
+}
+
+# Do the reverse-step test
+gdb_test_no_output "record" "turn on process record"
+
+set bp_main_return [gdb_get_line_number "TAG: main return"
$srcfile]
+gdb_breakpoint $srcfile:$bp_main_return
+gdb_continue_to_breakpoint "run to end of main, reverse-step
test" ".*$srcfile:$bp_main_return.*"
+gdb_test "display \$pc" ".*pc =.*" "display pc, reverse-step test"
+
+# At this point, GDB has already recorded the execution up until
the return
+# statement. Reverse-step and test if GDB transitions between
lines in the
+# expected order. It should reverse-step across lines 8, 5, 3, 2
and 1.
+foreach line {8 5 3 2 1} {
+ gdb_test "reverse-step" ".*TAG: line $line.*" "reverse step to
line $line"
+}
+
+## Clean restart, test reverse-next command
+clean_restart ${testfile}
+runto_main
+gdb_test_no_output "record" "turn on process record, reverst-next
test"
+
+set bp_main_return [gdb_get_line_number "TAG: main return"
$srcfile]
+gdb_breakpoint $srcfile:$bp_main_return
+gdb_continue_to_breakpoint "run to end of main, reverse-next
test" ".*$srcfile:$bp_main_return.*"
+gdb_test "display \$pc" ".*pc =.*" "display pc, reverse-next test"
+
+# At this point, GDB has already recorded the execution up until
the return
+# statement. Reverse-next and test if GDB transitions between
lines in the
+# expected order. It should reverse-next across lines 8, 5, 3, 2
and 1.
+foreach line {8 5 3 2 1} {
+ gdb_test "reverse-next" ".*TAG: line $line.*" "reverse next to
line $line"
+}

It seems like the step and next tests are identical, so I guess it
could
be factored out using:

foreach_with_prefix method {step next} {
...
}

?

Yup, redid the code using the foreach_with_prefix.

>
Simon
> yR